Whats the best watering divice out there?

So i'll have close to 50 Chickens from Bannies and Standards to Giants well I have been using 50 gallon buckets that i cut in half and sand down smooth. Well I went out of town and Dad did not clean the watering buckets just dumped and re- filled them. I keep getting this green stuff (I think Algee) in there to the point that sand paper wont remove. I tried the metal cover water that you hang up and they refuse to drink out of it. I have chick watering things in there but is there anything else out there that I don't have to refill a couple times a day I don't think they will do the nipple things either. Should I just remake the old ones and if so how do I keep the algee out.

Clorox will clean the algae from your waterers. Just pour some in it and let it set for a couple of hr's and then rinse. Just dont let the birds drink the clorox/water mix.

I have been considering using some 4in pvc pipe and drilling holes for my birds to stick their heads in to drink. I would cap the ends and use a float valve to regulate the water level and just hook a garden hose to the float valve. If You dont have running water close to the pen, you could use a plastic barrel filled with water and a small hose to gravity feed water to the float valve in the pvc pipe.

Right now I am using the 5gal plastic waters in each pen, but my pens only hold around 6 birds each. I bought a large rubbermaid tub with lid that I keep full of a clorox water mix. I soak my waters in the rubbermaid tub at least once a week to clean. Since I have extra waters for each pen, its simply a matter of swapping the dirty one for a clean one.

Yeah, ACV is apple cider vinegar. They recommend the natural or organic vinegar with "mother" in it - the sediment that lays in the bottom of the bottle. You can usually find this in your usual grocery store.